1. Field of the Invention
The present invention relates to a pivotal shaft device, especially to a pivotal shaft device assembled on a protection cover (or protection component), the protection cover (or protection component) is used in an electronic device such as a tablet compute or a communication products for providing a protection effect.
2. Description of Related Art
The tablet computer is an electronic device which is easy to be carried around and simple in operation, the adopted input method is to utilize a virtual keyboard or hand writing identification system installed on a touch screen, thereby saving the installation of a solid keyboard and mouse. For protecting the touch screen of the tablet computer, skilled people in the art have developed several structures for protection cover, the protection covers are usually installed with a foldable plate member and a pivotal shaft device, the mentioned conventional pivotal shaft device mainly includes two connection pieces and two pivotal shafts, the two pivotal shafts are located in parallel with each other and respectively pivoted between the two connection pieces, wherein one of the pivotal shafts is directly or indirectly combined at one side of the tablet computer, the other pivotal shaft is pivoted at one side of the foldable plate member; so when not being used, the foldable plate member is covered on the touch screen of the tablet computer thereby providing the protection effect; when being used, the foldable plate member is lifted and folded thereby forming a support allowing the tablet computer to lean against.
In the pivotal shaft combined with tablet computer, an opened slot is radially formed on the pivotal shaft, a concave magnetic shunt is installed in the opened slot, two sides of the magnetic shunt are respectively installed with an insertion plug thereby fastening the magnetic shunt in the opened slot, and plural first magnetic units are installed in the magnetic shunt, and a protection label is provided at the opening of the opened slot thereby allowing the magnetic shunt and the plural first magnetic units to be sealed in the opened slot, one side of the tablet computer is correspondingly installed with plural second magnetic units for achieving mutual magnetic attraction, such that the pivotal shaft can be detachably combined with the tablet computer; the “Accessory device and pivoting magnetic assembly” disclosed in the U.S. patent application Ser. Nos. 29/375,197, 61/384,179 and 12/971,62 are examples of the conventional pivotal shaft device.
However, the two pivotal shafts are fixed at certain locations between the two connection pieces, so the two pivotal shafts can only individually rotate, and a relative sliding movement (i.e. one pivotal shaft is moved for being away from or close to the other pivotal shaft) is unable to be generated between the two pivotal shafts, so when the protection cover is desired to be used in a tablet computer having a greater thickness, the foldable plate member may not be able to completely cover the touch screen; moreover, the foldable plate member is a soft leather cover, the pivotal connecting location of the soft leather cover and the other pivotal shaft is restrained by the other pivotal shaft thereby not being able to adjust the location along with the applied pulling force, so the mentioned pivotal connecting location is more easily to be frequently pulled or overly pulled, the pivotal connecting location of the soft leather cover is therefore fragile and easy to be broken, the mentioned disadvantage is the issue that the present invention aims to solve.
For solving the mentioned disadvantage, the present invention provides a pivotal shaft device having effects of sliding movement and recovering positioning thereby improving the capability of fitting with a wider range of thickness and increasing the operation convenience.